Safety guard for mandrel presses



' Oct 1937. J. M. EHRMANTRAUT 2,095,971

SAFETY .GUARD FOR MANDREL PRESSES Filed Aug. 6, 1936 2 Sheets-Sheet 2 J 70c JZCZ' 1071mm zifor/mey Patented Oct. 19, I937 UNI HEQ STATES PATENT ()FFECE Application August 6,

6 Claims.

1936, Serial No. 94,576

(Granted under the act of March 3, 1883, as

amended April 30,

This invention has for an object to provide a safety guard for use in combination with a mandrel press used in loading explosives.

There is an ever present danger of an accident occurring when explosives are being loaded, such as when making fulminate caps, detonators, or the like, wherein it is necessary to press or mold the explosive into compact form within a receptacle, with, of course, the resultant possibility of injury to the operator. With this invention, however, the pressing or molding takes place behind a door having a safety glass window so that the operator can watch the action and at the same time be safe from injury should an explosion occur.

A further feature of this invention is to so connect the safety door to the press that the usual operation of the press serves first to close the door before any actual pressing action takes place, and second to cause the pressing or molding action to take place in a manner visible to the operator.

A further feature of this invention is to adjustably connect the door to the press so that it may be set for different sized molds and pressure springs, and so that the normal operation of the press in the customary manner automatically closes the door before the actual pressing operation commences, and when the operation is over reopens the door after the pressure is completely released, thereby removing all possibility of danger of accident.

As a further feature, the guard is open at the top to permit expansion caused by accidental explosions.

With the foregoing and other objects in view, the invention consists in the construction, combination and arrangement of parts, as will be described more fully hereafter.

In the drawings:

Fig. 1 is a front plan view of the safety guard as applied to the mandrel press; 4

Fig. 2 is a side view looking from the right of Fig. 1, and

Fig. 3 is a sectional view on line 3-3 of Fig. 2.

There is shown at It a mandrel press which includes a pressure spring base H on which is placed the mold l 2 which receives the plunger I3 for molding the powder therein in the customary manner. The press rack 14 is operated against the plunger l3 by means of the shaft l5 carrying the hand lever I6. Door guides ll placed on each side of the front of the press It! carry between them an explosion-proof door I8 provided with a safety glass window l9, this window being of sufiicient strength to resist the direct force of any explosion that may take place within the press, the top of the press being open, as customary, to allow expansion of the exploding gases upwardly.

The door guides ll permit the door E8 to slide up or down, and the door I8 is supported by a pair of links 20, to which is attached a chain 2 I. A small tension spring 22 has one end anchored to the door l8 at 23 and the other end anchored to the upper end of the upper link 28, as at 24, so as to pivot the links and take up the slack in the chain 2| when the door is in the closed position. The chain 2| is attached to the periphery of the pulley 25 secured on a shaft 26 to which is likewise secured a pinion 21, the shaft being journalled on a pair of supporting arms 28 above the press It). A brace 29 and an arm 3|] also provide for holding the shaft 26 steady.

Secured to the top of the press rack M as at 3! is an angle iron arm 32 which is slotted, as at 33, and to which an angle iron door rack 34 is adjustably secured by means of the wing nut and bolt 35 extending through the slot 33. One of the supporting arms 28 is provided with a locking pin aperture 36 through which a locking pin may be inserted to hold the pulley 25 against rotation while the door is in the open position, thus permitting the rack 34 to be adjusted on the angle iron arm 32 according to the size of mold and pressure spring being used within the press.

In operation the angle iron door rack 34 is adjusted relative to the press rack l4 so as to permit the door l8 to reach the fully closed position while the press rack I4 is at least a slight distance above the top of the plunger 13 such as shown in Fig. 2. Initial rotation of the hand lever It causes the door l8 to reach the fully closed position while the press rack l4 reaches the position shown in dash outline in Fig. 2.

Continued anti-clockwise rotation of the handle Hi to the position shown in I6 then operates the plunger Hi to mold the powder in the press while the door l8 remains fully closed and the links 20 pivot to the position shown at 28 in Fig. 1, under the action of the spring 22, thus taking up the slack in the chain 2 I.

In completing the operation the hand lever i6 is then reversed in rotation in a clockwise position, first raising the press rack Hi from the plunger l3 until the pressure is entirely relieved, and then with all danger of accident removed as the lever continues in rotation, the door It is raised, permitting the loaded cap to be removed and a new cap to be placed therein ready for loading.

As is apparent, an explosion due to pressure can take place only while pressure is exerted against the plunger 13. The door [8 is always in closed position while the press rack is in contact with the plunger 43, so that should an accident occur the expanding gases will rise upwardly and pass out harmlessly through the open top, and cannot injure the operator on the other side of the glass door 18. 7

Other modifications and changes in the proportions and arrangements of the parts may be made by those skilled in the art, without departing from the nature and scope of the invention, as defined in the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment'of any royalties thereon or therefor.

Having thus set forth and disclosed the nature of this invention, what is claimed is:

1. A safety guard for a mandrel press used in loading explosives, comprising a pair of door guides secured to the front of the press, a safety explosion proof door vertically slidable in said door guides, and means for opening and closing said door secured to the press operating mechanism, said means including a lost motion device for maintaining said door closed before, during and after the pressure is exerted by the press.

2. A safety guard for a mandrel press used in loading explosives, comprising a 'pair of door guides secured to the front of the press, a safety explosion proof door vertically slidable in said door guides, and means for opening and closing said door secured to the press operating mechanism, said means maintaining said door closed before, during and after the pressure is exerted by the press, said safety door including an explosion-proof safety window permitting the operation to be visible.

3. A safety guard for a mandrel press used in,

loading explosives, comprising a pair of door guides secured to the front of the press, a safety explosion proof door vertically slidable in said door gm'des, and means for opening and closing said door secured to the press operating mechanism, said means maintaining said door closed before, during and after the pressure is exerted by the press, said opening and closing means being adjustable to provide for different sized molds within the press.

, 4. A safety guard for a mandrel press used in loading explosives, comprising a pair of door guides secured to the front of the press, a safety door vertically slidable in said door guides, and means for opening and closing said door secured to the press operating mechanism, said means maintaining said door closed While the pressure is exerted by the press, said opening and closing means including a chain linked at one end to said door, a pulley having the other end of the chain anchored thereto, a pinion for operating said pulley, and a door rack for operating saidpinion.

5. A safety guard for a mandrel press used in loading explosives, comprising a pair of door guides secured to the front of the press, a safety door vertically slidable in said door guides, and means for opening and closing said door secured to the press operating mechanism, said means maintaining said door closed while the pressure is exerted by the press, said opening and closing means including a chain linked at one end to said door, a pulley having the other end of the chain anchored thereto, a pinion for operating said pulley, and a door rack for operating said pinion, said door rack being adjustably secured relative to the press rack.

6. A safety guard for a mandrel press used in loading explosives, comprising a pair of door guides secured to the front of the press, a safety door vertically slidable in said door guides and means for opening and closing said door secured to the press operating mechanism, said means maintaining said door closed while the pressure is exerted by the press, said opening and closing means including a chain linked at one end to said door, a pulley having the other end of the chain anchored thereto, a pinion for operating said pulley, a door rack for operating said pinion, and means for taking up slack of the chain when the door is closed.

JOHN M. EHRMANTRAUT. 

